Added a 20ms sleep after the resize coefs have been written

Just like a 20ms sleep is needed after writing each new coefficient,
it is required to wait a few milliseconds after writing the last
register before running the IPU. Otherwise, garbage appear on the
screen when the coefficients change.
Always clear the STATUS register before running the IPU

Otherwise, the IPU won't run the very first time it is configured,
but only the following times.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Fix height value written in the size register

Apparently, it has to be (height + 1). For instance, if the output
buffer is 320x240, then a height of 241 should be written. Otherwise,
the IPU will skip the last line. This is particularly visible in
direct-connect mode, as the frame moves from bottom to top at a speed
of 60 pixels per second.